Potential red-emitting phosphor for white LED solid-state lighting

The phosphors Sr1-xMoO4:Eu-x(3+), KxSr1-2xMoO4:Eu-x(3+) were prepared by solid-state reaction technique at 800 degrees C. The intense red-emitting phosphor K0.25Sr0.50MoO4:Eu-0.25(3+) with tetragonal structure was obtained. The result indicated that KxSr1-2xMoO4:Eu-x(3+) phosphors can be excited effectively at 393 nm and 464 rum light. The presences of the K+ ion strengthen the absorption of the phosphors around 400 nm. Compared with Y2O2S:0.05Eu(3+), the obtained K0.25Sr0.50MoO4:Eu-0.25(3+) phosphor shows an enhanced red emission under 393 nm excitation. The strong red-emission lines around 616 nm correspond to the forced electric dipole D-5(0) -> F-7(2) transitions on Eu3+. The chromaticity coordinates (x = 0.64, y = 0.35) are close to the standard of NTSC (National Television Standard Committee). The optical properties suggest that K0.25Sr0.50MoO4:Eu-0.25(3+) is an efficient red-emitting phosphor for light emitting diode (LED) applications. (C) 2008 Elsevier B.V. All rights reserved.